Almond (Prunus dulcis L.) is one of the most important nut crops in Iran. Most almond cultivars and genotypes are self-incompatible. However, research on S-alleles indicates that it is very efficient in cultivar selection. Selfincompatibility in almond is gametophytic and controlled by a single S-locus with multiple codominant alleles. In this study, compatibility relationships among cultivars, “Tuono”, “Shokofeh”, “Sahand” and five improved genotypes “A1.16”, “A9.7”, “A8.39”,“A10.11” and “A230,” was investigated by the PCR of S-alleles. Degenerate primers (PaConsI-F, EMPC1consRD, EM-PC2consFD, and EM-PC3consRD) were used for amplification of S-alleles. Results showed that only “A10.11” and “A8.39” were completely cross-incompatible, but all of the other studied cultivars and genotypes were crosscompatible. Furthermore, cultivar “Tuono” and genotype “A1.16” had a self-fertility allele.